1) Field of the Invention
The present invention relates to vehicle headlamps having a variable light distribution mechanism. More specifically, the present invention relates to vehicle headlamps in which a projector-type lamp unit can be rotated about an axis to change the direction of light irradiated by a lamp unit.
Further, the present invention relates to an opposite holding type pivot mechanism, in the vehicle headlamp having the variable light distribution mechanism, that pivotally supports the lamp unit on a frame by holding at opposite ends as well as rotatably about the rotation axis.
In the following description, “vertical direction” and “horizontal direction” indicate “vertical direction” and “horizontal direction” when the vehicle headlamp and the opposite holding type pivot mechanism for the vehicle headlamp of the present invention is mounted on a vehicle.
2) Description of the Related Art
A vehicle headlamp having a variable light distribution mechanism is disclosed, for example, in French Patent Publication (FR 2 760 069 A1). This vehicle headlamp comprises a lamp housing that is divided into a lamp chamber and a lamp lens. A projector-type lamp unit and a frame are arranged in the lamp chamber. The projector-type lamp unit is mounted on the frame via the variable light distribution mechanism and can rotate about an axis (hereinafter, “rotation axis”). The frame is mounted on the lamp housing via an light axis adjusting mechanism.
In this vehicle headlamp, the direction of light irradiated by the lamp unit is changed by rotating the projector-type lamp unit about the rotation axis via the variable light distribution mechanism. The rotation of the projector-type lamp unit is performed based on information about running condition (hereinafter “vehicle running state information”), road information, map information, position information, and the like. In this manner, the vehicle headlamp can ensure the safety by controlling the light distribution optimally corresponding to the road shape, running speed and the like. For example, the driver's field of vision and visibility at the time of nighttime driving can be improved, by changing the light irradiation direction towards the steering direction of the vehicle. Such a system is well known, and referred to as an adaptive front lighting system (AFS).
However, this vehicle headlamp has a problem in appearance, since the projector-type lamp unit in the lamp chamber, the frame, the variable light distribution mechanism, and the light axis adjusting mechanism can be seen through the lamp lens.
Vehicle headlamps that aim to solve the problem of appearance has been disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2002-231015 and 2002-367410. The headlamp disclosed in Japanese Patent Application Laid-Open No. 2002-231015 has a configuration such that an extension (4) is arranged between a lamp unit and an outer lens (5), and a standing wall (6) is provided in a reflector (1) of the lamp unit. Because of the provision of the standing wall (6), the back of the reflector (1) is not seen through the outer lens (5) even if the reflector (1) rotates, and, as a result, the appearance becomes better.
The headlamp disclosed in Japanese Patent Application Laid-Open No. 2002-367410 has a configuration such that an inner panel (60) is arranged between a lamp unit and an outer lens (5), and dummy portions (13a) and (13b) are provided in a reflector (4) of the lamp unit. Because of the provision of the dummy portions (13a) and (13b), the field of vision in the depth direction on the back side of the reflector (4) through the outer lens (5) is blocked even if the reflector (4) is rotated, and, as a result, the appearance becomes better.
In these two headlamps, however, the lamp unit is not the projector-type lamp unit, but a lamp unit of a type that irradiates the reflected light from the reflector (1) or the reflector (4) to the outside. Therefore, it is difficult to directly apply the technique of the above two vehicle headlamps to the vehicle headlamp having a projector-type lamp unit. In other words, since the projector-type lamp unit has a projection lens (condenser lens such as convex lens)that projects the reflected light from the reflector, and a lens holder for supporting the projection lens, this projection lens and the lens holder rotate with a rotation of the lamp unit. Therefore, it is necessary to improve the appearance, without disturbing the rotation of the projector-type lamp unit.
In the vehicle headlamp having the variable light distribution mechanism, the lamp unit is pivotally supported on the frame rotatably about the rotation axis. Particularly, in the case of the opposite holding type pivot mechanism, since the lamp unit is pivotally supported on opposite sides, it is effective against vibrations of the vehicle. It is necessary to pivotally support the lamp unit on the frame easily and at a low price, via the opposite holding type pivot mechanism.